1. Field of the Invention
The invention relates to a method and apparatus for acquiring, recording and storing information in photographic and electronic media. In particular, the invention relates to image recording and specifically to recording two-dimensional images, such as are found in electrophoretic patterns, along with associated alpha-numeric information. A method and apparatus of comparison of images is disclosed.
2. Description of the Prior Art
Electrophoresis is an electrochemical process in which colloidal particles or macromolecules having a net electric charge migrate in a solution under the influence of an electric field. The process is widely accepted and used, resulting in an enormous body of information and data.
Biological mixtures, such as proteins or nucleic acids (DNA or RNA) are often separated by electrophoresis in flat gels, yielding either a one-dimensional train or ladder of bars, or a two-dimensional pattern of spots. In either case, the result is a flat pattern to be analyzed visually or by computerized methods.
The gels containing the primary information, that is, the image pattern, are fragile. Accordingly, a photographic record is usually made for archival purposes, typically for reference or for use as an illustration in a scientific publication. In some instances, the photograph is part of the documentation for diagnostic records, or it may be part of a new drug application. In addition, a high resolution electronic image may be made from the image pattern for record-keeping and research purposes.
Because of the tremendous amount of information generated photographically and electronically, good record keeping is essential. Typically, among the requirements of good record keeping are positive image identification and inclusion in the photographic image of identifying and descriptive information pertaining to the image. The information depicted in the photograph, including the identifying and descriptive information, may be computer-stored as a retrievable digital image. If image analysis is performed on the pattern, the resulting image analysis data may also be retrievably stored.
It is important that the image recorded be accurate and clear because, once the gel is disposed of, the only source of information is the photographic or electronic image. The characteristics of gel images create special lighting problems which make reproduction of the images difficult. For example, a major portion of the field in a gel image is transparent. Thus, the amount of light necessary to adequately illuminate the image often produces a flare or excessive brightness which overwhelms the small spots which constitute the image, whereby the information contained in the image may be lost and the dynamic range recorded is reduced.
When it is desired to make both electronic and photographic reproductions of the gel image, separate, multi-step processes are required. However, the fragility of the gel medium, coupled with the multi-step processes, makes it difficult to handle a great number of images at any one time. Also, if great care is not taken, it is possible to destroy the gel before the information is acquired.
Typically, the information contained in a pattern is cross-checked and compared with the information in other similar or diverse patterns. Thus, ease of retrieval enabling inter-comparison is an important and desirable feature of any recording and storage system.
In order to illustrate the importance of a simple, efficient and accurate system, it is instructive to consider construction of the Human Protein Index, in which hundreds of thousands of two-dimensional electrophoretic patterns must be analyzed, or sequencing the DNA of the entire human genome which will ultimately require the analysis and storage of data from many millions of gels. For either of these projects an automatic, efficient and accurate system for acquiring, recording and storing the information associated with these gels is essential if significant progress towards analysis of the primary information is to be made.
Prior art systems have not comprehensively addressed the foregoing problems. The importance of the present invention lies in its comprehensive approach to satisfying the record-keeping requirements associated with photographic reproduction and electronic imaging of large numbers of fragile images. The system permits simultaneous photographic recording and electronic imaging and storage using an optical system compatible with photographic and electronic media. Recording is accomplished in one or a few steps, and a simple method of image storage, retrieval and inter-comparison is provided.